Seismic Sensor Pairing for Ghost Signal Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Marine seismic surveying is hindered by ghost signals resulting from reflections at the air-water interface, which reduce the accuracy of subterranean structure representations in measurement data.
Innovation Solution
The use of pairs of seismic sensors oriented in opposite directions allows for the combination of measurement data to isolate pressure signals and vector signals, enabling the removal of ghost signals through deghosting processes, including scaling and summation techniques based on acoustic impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If seismic sensors are used to detect reflected seismic waves in marine environment, then subterranean structure imaging is enabled, but ghost signals are generated that reduce measurement accuracy
Solution Approach 1:
The seismic sensor output is segmented into two independent components: pressure signal and particle motion signal. This is achieved by using a pressure-sensitive seismic sensor and combining it with a particle motion sensor, allowing the pressure component to be isolated and used for deghosting processing while maintaining the original imaging capability.
Solution Approach 2:
An intermediary processing step is introduced between the raw sensor data and the final image representation. This intermediary deghosting process uses the pressure signal to create a corrected seismic wavefield that eliminates ghost signals before the data is used for subterranean structure imaging, thereby improving measurement precision without losing imaging capability.
2Loss of information
If seismic waves are propagated into subterranean structure and reflected back, then structural information is obtained, but ghost signals appear in measurement data
Solution Approach 1:
The harmful ghost signal component is extracted and separated from the useful seismic wavefield information. By isolating the pressure signal component and using it specifically for deghosting processing, the ghost signals are removed from the final measurement data while preserving all structural information content from the subterranean reflections.
Solution Approach 2:
The pressure signal, which was originally just one component of the seismic wave measurement, is converted into a useful tool for eliminating ghost signals. The pressure component that was previously part of the problematic ghost signal generation is now used as a corrective element to remove those same ghost signals from the data.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of subterranean structure representations by effectively eliminating ghost signals, allowing for more precise imaging of subterranean structures.
Implementation Method 1
Each of the first and second seismic sensors has a sensing element responsive to pressure and particle motion
Implementation Method 2
A seismic wave generated by a seismic source is propagated generally downwardly into the subterranean structure
Implementation Method 3
A reflected seismic wave (that is in response to the seismic wave propagated by the seismic source) propagates generally upwardly toward an arrangement of seismic sensors
Implementation Method 4
Each of the first and second seismic sensors has a sensing element responsive to pressure and particle motion
Data Source
AI summary
Measurement data is received from first and second seismic sensors, where the first and second seismic sensors are oriented in opposite directions. Each of the first and second seismic sensors has a sensing element responsive to pressure and particle motion. The signals can be combined to remove the particle motion component of the measurement data and obtain pressure-only data. Alternatively, the signals can be combined to deghost the received measurement data.